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Vascular Pharmacology Jun 2024Capillaries are the smallest blood vessels (<10 μm in diameter) in the body and their walls are lined by endothelial cells. These microvessels play a crucial role in... (Review)
Review
Capillaries are the smallest blood vessels (<10 μm in diameter) in the body and their walls are lined by endothelial cells. These microvessels play a crucial role in nutrient and gas exchange between blood and tissues. Capillary endothelial cells also produce vasoactive molecules and initiate the electrical signals that underlie functional hyperemia and neurovascular coupling. Accordingly, capillary function and density are critical for all cell types to match blood flow to cellular activity. This begins with the process of angiogenesis, when new capillary blood vessels emerge from pre-existing vessels, and ends with rarefaction, the loss of these microvascular structures. This review explores the mechanisms behind these processes, emphasizing their roles in various microvascular diseases and their impact on surrounding cells in health and disease. We discuss recent work on the mechanisms controlling endothelial cell proliferation, migration, and tube formation that underlie angiogenesis under physiological and pathological conditions. The mechanisms underlying functional and anatomical rarefaction and the role of pericytes in this process are also discussed. Based on this work, a model is proposed in which the balance of angiogenic and rarefaction signaling pathways in a particular tissue match microvascular density to the metabolic demands of the surrounding cells. This negative feedback loop becomes disrupted during microvascular rarefaction: angiogenic mechanisms are blunted, reactive oxygen species accumulate, capillary function declines and eventually, capillaries disappear. This, we propose, forms the foundation of the reciprocal relationship between vascular density, blood flow, and metabolic needs and functionality of nearby cells.
PubMed: 38857638
DOI: 10.1016/j.vph.2024.107393 -
Annals of Plastic Surgery Jun 2024Management of vasospastic and vaso-occlusive disorders is a complex challenge, with current treatments showing varied success. Cannabinoids have demonstrated both...
BACKGROUND
Management of vasospastic and vaso-occlusive disorders is a complex challenge, with current treatments showing varied success. Cannabinoids have demonstrated both vasodilatory and antifibrotic properties, which present potential mechanisms for therapeutic relief. No existing review examines these effects in peripheral circulation in relation to vasospastic and vaso-occlusive disorders. This study aims to investigate vasodilatory and antifibrotic properties of cannabinoids in peripheral vasculature for application in vasospastic and vaso-occlusive disorders affecting the hand.
METHODS
A systematic search was conducted by 2 independent reviewers across PubMed, Cochrane, Ovid MEDLINE, and CINAHL to identify studies in accordance with the determined inclusion/exclusion criteria. Information regarding study design, medication, dosage, and hemodynamic or antifibrotic effects were extracted. Descriptive statistics were used to summarize study findings as appropriate.
RESULTS
A total of 584 articles were identified, and 32 were selected for inclusion. Studies were grouped by effect type: hemodynamic (n = 17, 53%) and antifibrotic (n = 15, 47%). Vasodilatory effects including reduced perfusion pressure, increased functional capillary density, inhibition of vessel contraction, and increased blood flow were reported in 82% of studies. Antifibrotic effects including reduced dermal thickening, reduced collagen synthesis, and reduced fibroblast migration were reported in 100% of studies.
CONCLUSION
Overall, cannabinoids were found to have vasodilatory and antifibrotic effects on peripheral circulation via both endothelium-dependent and independent mechanisms. Our review suggests the applicability of cannabis-based medicines for vasospastic and vaso-occlusive disorders affecting the hand (eg, Raynaud disease, Buerger disease). Future research should aim to assess the effectiveness of cannabis-based medicines for these conditions.
Topics: Humans; Cannabinoids; Vasodilator Agents; Antifibrotic Agents; Fibrosis
PubMed: 38857012
DOI: 10.1097/SAP.0000000000003985 -
Journal of the Endocrine Society May 2024Vasoactive intestinal peptide (VIP)-secreting tumors (VIPomas) are digestive neuroendocrine tumors in which the hormonal secretion is life-threatening. Biological...
BACKGROUND
Vasoactive intestinal peptide (VIP)-secreting tumors (VIPomas) are digestive neuroendocrine tumors in which the hormonal secretion is life-threatening. Biological confirmation is obtained by demonstrating an elevation in plasma VIP, usually using radioimmunoassay (RIA). In some cases, analytical interference is suspected. We developed 3 different techniques to detect interference in VIP RIA.
METHODS
Three techniques were used: RIA after Sephadex column chromatography separation, RIA after polyethylene glycol precipitation, and I-labeled VIP binding test. We included patients with suspicion of false positive VIP (FPV) elevation. We then compared results with those of a group of "real," proven VIPoma (RV).
RESULTS
A total of 15 patients with FPV elevation and 9 RV patients were included. Interference was detected in all FPV patients vs none in RV. Clinical and biochemical parameters did not differ between FPV and RV patients, but VIP concentration in RIA was significantly higher in FPV patients than in RV patients (228 pmol/L vs 66 pmol/L, = .038). Using a I-labeled VIP binding test, median proportion of radioactivity in the pellet was significantly higher in FPV than in RV patients (53% vs 13%, < .0001). A 20.5% threshold presented excellent performances (sensitivity 100% [79.6-100], specificity 100% [70.1-100]).
CONCLUSION
We developed 3 different laboratory techniques to reveal interference in RIA VIP assays. The diagnostic performance of all 3 was excellent. These techniques must be employed in cases of discordance between VIP elevation and clinical presentation.
PubMed: 38854908
DOI: 10.1210/jendso/bvae102 -
Cureus May 2024Introduction Propofol is a phenol agent with sedative and anesthetic properties that has been in use for decades, but with controversy in critically ill pediatric...
Introduction Propofol is a phenol agent with sedative and anesthetic properties that has been in use for decades, but with controversy in critically ill pediatric patients, given the concern for developing propofol-related infusion syndrome (PRIS). Our aim was to assess the risk of propofol infusions in the pediatric intensive care unit (PICU) at doses and durations greater than the described safety data and its associated covariables. Methods Retrospective cohort analysis of 173 patients receiving propofol in the PICU. Patients were categorized as receiving greater or less than 48-hour infusions. Demographic data and daily clinical variables were recorded for up to seven days post-infusion initiation or until infusion was stopped. Results In this descriptive analysis, patients' demographics were similar, but admission diagnosis was not. Both groups received high mean doses of propofol (>67 mcg/kg/min), with no cases of PRIS observed. The illness severity scores and the need for vasoactive infusion support varied between the cohorts, with higher illness scores and a higher percentage of subjects requiring vasoactive agents in the >48-hour cohort. Finally, there were no major differences in lactate levels or biochemical characteristics between the two groups. Conclusions This study provides pilot data in relation to the feasibility of propofol infusion in critically ill pediatric patients and underscores the need for a larger multicenter study to draw clinical recommendations.
PubMed: 38854299
DOI: 10.7759/cureus.59948 -
Transplant International : Official... 2024This study aimed to assess the lung transplantation (LT) outcomes of patients with right ventricular dysfunction (RVD), focusing on the impact of various extracorporeal... (Comparative Study)
Comparative Study
Outcomes of Lung Transplantation in Patients With Right Ventricular Dysfunction: A Single-Center Retrospective Analysis Comparing ECMO Configurations in a Bridge-to-Transplant Setting.
This study aimed to assess the lung transplantation (LT) outcomes of patients with right ventricular dysfunction (RVD), focusing on the impact of various extracorporeal membrane oxygenation (ECMO) configurations. We included adult patients who underwent LT with ECMO as a bridge-to-transplant from 2011 to 2021 at a single center. Among patients with RVD ( = 67), veno-venous (V-V) ECMO was initially applied in 79% (53/67) and maintained until LT in 52% (35/67). Due to the worsening of RVD, the configuration was changed from V-V ECMO to veno-arterial (V-A) ECMO or a right ventricular assist device with an oxygenator (Oxy-RVAD) in 34% (18/67). They showed that lactic acid levels (2-6.1 mmol/L) and vasoactive inotropic score (6.6-22.6) increased. V-A ECMO or Oxy-RVAD was initiated and maintained until LT in 21% (14/67) of cases. There was no significant difference in the survival rates among the three configuration groups (V-V ECMO vs. configuration changed vs. V-A ECMO/Oxy-RVAD). Our findings suggest that the choice of ECMO configuration for LT candidates with RVD should be determined by the patient's current hemodynamic status. Vital sign stability supports the use of V-V ECMO, while increasing lactic acid levels and vasopressor needs may require a switch to V-A ECMO or Oxy-RVAD.
Topics: Humans; Extracorporeal Membrane Oxygenation; Male; Lung Transplantation; Retrospective Studies; Female; Middle Aged; Ventricular Dysfunction, Right; Adult; Treatment Outcome; Heart-Assist Devices; Aged
PubMed: 38845757
DOI: 10.3389/ti.2024.12657 -
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue May 2024To construct and validate a nomogram model for predicting the risk of 28-day mortality in sepsis patients.
OBJECTIVE
To construct and validate a nomogram model for predicting the risk of 28-day mortality in sepsis patients.
METHODS
A retrospective cohort study was conducted. 281 sepsis patients admitted to the department of intensive care unit (ICU) of the 940th Hospital of the Joint Logistics Support Force of PLA from January 2017 to December 2022 were selected as the research subjects. The patients were divided into a training set (197 cases) and a validation set (84 cases) according to a 7 : 3 ratio. The general information, clinical treatment measures and laboratory examination results within 24 hours after admission to ICU were collected. Patients were divided into survival group and death group based on 28-day outcomes. The differences in various data were compared between the two groups. The optimal predictive variables were selected using Lasso regression, and univariate and multivariate Logistic regression analyses were performed to identify factors influencing the mortality of sepsis patients and to establish a nomogram model. Receiver operator characteristic curve (ROC curve), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) were used to evaluate the nomogram model.
RESULTS
Out of 281 cases of sepsis, 82 cases died with a mortality of 29.18%. The number of patients who died in the training and validation sets was 54 and 28, with a mortality of 27.41% and 33.33% respectively. Lasso regression, univariate and multivariate Logistic regression analysis screened for 5 independent predictors associated with 28-day mortality. There were use of vasoactive drugs [odds ratio (OR) = 5.924, 95% confidence interval (95%CI) was 1.244-44.571, P = 0.043], acute physiology and chronic health evaluation II (APACHE II: OR = 1.051, 95%CI was 1.000-1.107, P = 0.050), combined with multiple organ dysfunction syndrome (MODS: OR = 17.298, 95%CI was 5.517-76.985, P < 0.001), neutrophil count (NEU: OR = 0.934, 95%CI was 0.879-0.988, P = 0.022) and oxygenation index (PaO/FiO: OR = 0.994, 95%CI was 0.988-0.998, P = 0.017). A nomogram model was constructed using the independent predictive factors mentioned above, ROC curve analysis showed that the AUC of the nomogram model was 0.899 (95%CI was 0.856-0.943) and 0.909 (95%CI was 0.845-0.972) for the training and validation sets respectively. The C-index was 0.900 and 0.920 for the training and validation sets respectively, with good discrimination. The Hosmer-Lemeshoe tests both showed P > 0.05, indicating good calibration. Both DCA and CIC plots demonstrate the model's good clinical utility.
CONCLUSIONS
The use of vasoactive, APACHE II score, comorbid MODS, NEU and PaO/FiO are independent risk factors for 28-day mortality in patients with sepsis. The nomogram model based on these 5 indicators has a good predictive ability for the occurrence of mortality in sepsis patients.
Topics: Humans; Sepsis; Retrospective Studies; Nomograms; Risk Factors; Intensive Care Units; ROC Curve; Prognosis; Female; Male; Logistic Models; Hospital Mortality; Middle Aged; Aged
PubMed: 38845493
DOI: 10.3760/cma.j.cn121430-20231109-00961 -
The Journal of Physiology Jun 2024The brain requires an uninterrupted supply of oxygen and nutrients to support the high metabolic needs of billions of nerve cells processing information. In low oxygen...
The brain requires an uninterrupted supply of oxygen and nutrients to support the high metabolic needs of billions of nerve cells processing information. In low oxygen conditions, increases in cerebral blood flow maintain brain oxygen delivery, but the cellular and molecular mechanisms responsible for dilation of cerebral blood vessels in response to hypoxia are not fully understood. This article presents a systematic review and analysis of data reported in studies of these mechanisms. Our primary outcome measure was the percent reduction of the cerebrovascular response to hypoxia in conditions of pharmacological or genetic blockade of specific signaling mechanisms studied in experimental animals or in humans. Selection criteria were met by 28 articles describing the results of animal studies and six articles describing the results of studies conducted in humans. Selected studies investigated the potential involvement of various neurotransmitters, neuromodulators, vasoactive molecules and ion channels. Of all the experimental conditions, blockade of adenosine-mediated signaling and inhibition of ATP-sensitive potassium (K) channels had the most significant effect in reducing the cerebrovascular response to hypoxia (by 49% and 37%, respectively). Various degree reductions of the hypoxic response were also reported in studies which investigated the roles of nitric oxide, arachidonic acid derivates, catecholamines and hydrogen sulphide, amongst others. However, definitive conclusions about the importance of these signaling pathways cannot be drawn from the results of this analysis. In conclusion, there is significant evidence that one of the key mechanisms of hypoxic cerebral vasodilation (accounting for ∼50% of the response) involves the actions of adenosine and modulation of vascular K channels. However, recruitment of other vasodilatory signaling mechanisms is required for the full expression of the cerebrovascular response to hypoxia.
PubMed: 38843467
DOI: 10.1113/JP285060 -
Pediatric Cardiology Jun 2024Data comparing surgical systemic-to-pulmonary artery shunt and patent ductus arteriosus (PDA) stent as the initial palliation procedure for patients with pulmonary...
Data comparing surgical systemic-to-pulmonary artery shunt and patent ductus arteriosus (PDA) stent as the initial palliation procedure for patients with pulmonary atresia with intact ventricular septum (PA-IVS) are limited. We sought to compare characteristics and outcomes in a multicenter cohort of patients with PA-IVS undergoing surgical shunts versus PDA stents. We retrospectively reviewed neonates with PA-IVS from 2009 to 2019 in 19 United States centers. Bivariate comparisons and multivariable logistic regression analysis were performed to determine the relationship between initial palliation strategy and outcomes including major adverse cardiovascular events (MACE): stroke, mechanical circulatory support, cardiac arrest, or death. 187 patients were included: 38 PDA stents and 149 surgical shunts. Baseline characteristics did not differ statistically between groups. Post-procedural MACE occurred in 4 patients (11%) with PDA stents versus 38 (26%) with surgical shunts, p = 0.079. Overall, the initial palliation strategy was not significantly associated with MACE (aOR:0.37; 95% CI,0.13-1.02). In patients with moderate-to-severe right ventricle hypoplasia, PDA stents were significantly associated with decreased odds of MACE (aOR:0.36; 95% CI,0.13-0.99). PDA stents were associated with lower vasoactive inotrope scores (median 0 versus 5, p < 0.001), greater likelihood to be extubated at the end of their procedure (37% versus 4%, p < 0.001), and shorter duration of mechanical ventilation (median 24 versus 96 h, p < 0.001). PDA stents were associated with significantly more unplanned reinterventions for hypoxemia compared to surgical shunts (42% vs. 20%, p = 0.009). In this multicenter study, neonates with PA-IVS who underwent PDA stenting received less vasoactive and ventilatory support postoperatively compared to those who had surgical shunts. Furthermore, patients with the most severe morphology had decreased odds of MACE.
PubMed: 38842558
DOI: 10.1007/s00246-024-03529-2 -
Scientific Reports Jun 2024The maintenance of intestinal integrity and barrier function under conditions of restricted oxygen availability is crucial to avoid bacterial translocation and local...
The maintenance of intestinal integrity and barrier function under conditions of restricted oxygen availability is crucial to avoid bacterial translocation and local inflammation. Both lead to secondary diseases after hemorrhagic shock and might increase morbidity and mortality after surviving the initial event. Monitoring of the intestinal integrity especially in the early course of critical illness remains challenging. Since microcirculation and mitochondrial respiration are main components of the terminal stretch of tissue oxygenation, the evaluation of microcirculatory and mitochondrial variables could identify tissues at risk during hypoxic challenges, indicate an increase of intestinal injury, and improve our understanding of regional pathophysiology during acute hemorrhage. Furthermore, improving intestinal microcirculation or mitochondrial respiration, e.g. by remote ischemic preconditioning (RIPC) that was reported to exert a sufficient tissue protection in various tissues and was linked to mediators with vasoactive properties could maintain intestinal integrity. In this study, postcapillary oxygen saturation (µHbO), microvascular flow index (MFI) and plasmatic D-lactate concentration revealed to be early markers of intestinal injury in a rodent model of experimental hemorrhagic shock. Mitochondrial function was not impaired in this experimental model of acute hemorrhage. Remote ischemic preconditioning (RIPC) failed to improve intestinal microcirculation and intestinal damage during hemorrhagic shock.
Topics: Animals; Ischemic Preconditioning; Rats; Shock, Hemorrhagic; Microcirculation; Intestines; Male; Biomarkers; Disease Models, Animal; Mitochondria; Intestinal Mucosa; Lactic Acid
PubMed: 38839819
DOI: 10.1038/s41598-024-63293-4 -
American Journal of Medicine Open Jun 2023Patients admitted with pneumonia and heart failure (HF) have increased mortality and cost compared to those without HF, but it is not known whether outcomes differ...
BACKGROUND
Patients admitted with pneumonia and heart failure (HF) have increased mortality and cost compared to those without HF, but it is not known whether outcomes differ between systolic and diastolic HF. Management of concomitant pneumonia and HF is complicated because HF treatments can worsen complications of pneumonia.
METHODS
This is a retrospective cohort study from the Premier Database among patients admitted with pneumonia between 2010-2015. Patients were categorized based on systolic, diastolic, and combined HF using ICD-9 codes. The primary outcome was in-hospital mortality. Secondary outcomes included use of HF medications, length of stay, cost, intensive care unit (ICU) admission, as well as use of invasive mechanical ventilation (IMV), vasopressors and inotropes. Multivariable logistic regression was used to describe associations of these outcomes with type of HF.
RESULTS
Of 123,211 patients with pneumonia and HF, 41,196 (33.4%) had systolic HF, 69,982 (56.8%) diastolic HF, and 12,033 (9.8%) had combined HF. Compared to patients with diastolic HF, after multivariable adjustment systolic HF was associated with higher in-hospital mortality (OR 1.15; 95% CI:1.11-1.20), ICU admission, and use of IMV and vasoactive agents, but not with increased length of stay or cost. Among patients with systolic HF, 80% received a loop diuretic, 72% a beta blocker, 48% angiotensin converting enzyme inhibitor or angiotensin receptor blocker, and 12.5% a mineralocorticoid receptor antagonist.
CONCLUSION
Systolic HF is associated with added risk in pneumonia compared to diastolic HF. There may also be an opportunity to optimize medications in systolic HF prior to discharge.
PubMed: 38835731
DOI: 10.1016/j.ajmo.2022.100025